The tomb is basically located in the middle. Here is a cross section of the Great Pyramid of Giza. As you can see in the image, there are several access tunnels and at least two chambers, one for the king to be buried in and one for the queen. Most pyramids have a cross section similar to this. The exact number of chambers will be different, as will the configuration, but the chamber will be in the middle of the pyramid and a tunnel will lead in from outside.

Are these tunnels linear or do we see mazes/branches? And are there any traps like we see in the movies?